The invention relates to a method of cooling cast billets made of an aluminum alloy after a homogenizing anneal, and an apparatus for carrying out the method.
In aluminum foundries, billets, in particular large-size slugs and rolling ingots, are produced by known continuous casting processes. During casting, the metal solidifies in a cooled mold only in the region of the surface. After leaving the mold, the billet is dimensionally stable, but is still liquid in the interior. The continuously lowered billet is therefore intensively cooled further.
The cooling-down during the continuous casting is orientated towards allowing the casting process to proceed optimally with the solidification process. There is little or only slight scope for metallurgical concerns specific to the alloy.
The solidified, cast billets are therefore heated again as a rule and subjected to a homogenizing anneal in a full-annealing furnace. This can be done in the foundry or in the further-processing rolling mill or press shop, even after storage of the billets.
After the homogenizing anneal, the billets, if they are not directly hot-worked by the producer of the semifinished product, are cooled down, for example rapidly by immersing in water or slowly in air, depending on the alloy or application. These known cooling-down methods after the homogenizing anneal have the disadvantage that they proceed in an uncontrolled or poorly controlled manner.
The object of the present invention is to create a method and an apparatus of the type discussed above with which fully annealed billets can be cooled down in an automated and controlled manner in accordance with the alloy composition, the cross-section and the specific use.